The contraceptive mode of action is related both to an inflammatory reaction in the endometrium due to the presence of copper, and to a probable direct toxicity on spermatozoa.
There are different models of copper IUDs adapted to the different anatomical conditions of women (size of the uterus). It can be prescribed for women who have not had children under certain conditions (verification and information on the risks of genital infection, use of a small IUD). Its insertion is recommended during the menstrual period or just after. It can be removed at any time during the cycle. The usual duration is 3 or 5 years.

The main contraindications are an ongoing wanted pregnancy, an ongoing upper genital infection, a malformation of the uterus, unexplained vaginal bleeding, taking certain treatments that affect immunity, or allergies to copper.
Side effects include increased menstrual flow and pelvic pain.
Serious complications such as expulsion, perforation and genital infection are rare.